SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '508e83c63664b0dc10119484b54696da965ae9875f466664a85661f913703a34' 
  AND token = 's3OFevV7iPIwFLhaqNP+dMtHexW/NIDdV05e8ItYnJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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