SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b327cdd2dfa826a8aaa12f272a171a7b058d60d6107454b8039edea07a2b4be' 
  AND token = 'r+Ggx4RaQhRlTGd1O+sBTleVQwT+Lxtog3pnDLv7LCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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