SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3da17482a5d85c7d19753dc08afadfa4b84877afd3666f9e5efc3bf840347bd9' 
  AND token = 'W8+bGpJZqokwjmw5N75vo1Fa0+h6ugVSYoTyfFIon0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}