SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c35f390c92b1d43201ecf4fe2055e9a9a53f78dc132f8b7181c9b7ff56b3d882' 
  AND token = 'jA+3oThGxVWB/sJqQnTZkLWvm69I+ZsUsXPPDYy2IiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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