SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2902d448cd57432b264735938a416433bbf722e3711656a7c4252205d56b28aa' 
  AND token = 'M3mbjct5t4zIvGH55v1IaDSH/98k4ZoBlYdmQmMSc7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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