SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b843697d1978f16cf253e1ab72cdb3d95aa9ce3aa12c098a312cca9c1a2d369' 
  AND token = 'hCUrnnaIYyYMXHzCPKiFg06gNXgllrqpJqWURi0beJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}