SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c11eb4885176a7057c99dcada7f773bfcc6ea0cce48d436744d69f936abb1278' 
  AND token = '/RXJP8Io8cT0t6xKMPxWcLvzoDhVpDeWR7wjo+iK5Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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