SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3bf87a92b5da334211400d8eefe1cac96ec2d049413bd3a11e31fb8bfe8d569' 
  AND token = 'EoizZHTVbh9lfTpSjGQ4fA2VM9+UMsgrt9fnsGegVYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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