SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14640185d6318993847436ae846439fb9c65074889d2e11a7711801cf29ff498' 
  AND token = '1SDOvicz2LbfnJdG4bjYVsgSPE9iQvaAcX4KvqbOoew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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