SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4554cabf17e1fc4ef6fad96972d4fc75fc73c192aebf909caa1729257208328c' 
  AND token = 'msNE2AhGEL4oYnoT5f0arxhtcsOeEtmzFkMk+Asx4SU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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