SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '897eb0881bf4571d8136e31e90010960de138488b3f139fce2e83d4281f6602f' 
  AND token = 'JApPPWHn5m0uypGDmMJktTA7lTHWAjeedkG56SsuTIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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