SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1879ad7b717a60352ed7a26690169f7656683ff4a23c92f18827b9d73d20ad07' 
  AND token = 'MPYcYysJ29Fhde0+vRNFXI+WkCJDB4cGrc+OTzZjEKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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