SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aae8f44614505193ceaaba72250bc6f45e0b534a4d9025183543f044ba1b0686' 
  AND token = 'Pv7cVBqSPdJxOpoV1MOQmHYbBYjhDAeNwHIa0SwwD+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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