SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b6f269720e48c7eabf0cd4698df9f95d682ad137c1bb751ac335a695decad35' 
  AND token = '6JrM/qXKWkyPvvs0CpSgoh0xWI2ClZwI8tlHEVB9IUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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