SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6995949ac3e5df264d6c5247efb97ce9e998799d2897a80ff8bef9375686ef47' 
  AND token = 'nzIQb6hBTKwlE75ln++EYn1ACknutXMSYUCbu3frNhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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