SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e7608a7adc6cb16a8468abc6a3ccf3977eb540016503f10d460e473620d6b8b' 
  AND token = 'PvCSHdbc4/Y1G9G/xkKj8xymD4WwZgV0m5YAKaq1zXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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