SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50e83628c15ec1f9b994a6398ba14d42290b69b6b433a2fb407020501674fba0' 
  AND token = 'ZBTDRzCNChGgjh4jPjZILMe8Si/9i2UlICLIyjYmVek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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