SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7b96f167972390f600664f4728e81b5b02534f840af1e759a2353fa284d5992' 
  AND token = 'I9l3AeJcHyJcpVCJYq3dl8Mb+XdFsjgf3jRTaemKCYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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