SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66c290728e936c904dcd228754ff1558dc530e4f1539a1733130486c4e428d36' 
  AND token = 'GEp/CpLHwo5T6H7NwQWd+mGEFDho+hl5BAUvyGH3SYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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