SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2f84c573cef756295ce1804a660a0fa03961781b27cc2672c697e52bd8cb42f' 
  AND token = 'SSGd4yYsuVQnJTAW5Y2bHrODBZpGaP6PLUKC5yxvwdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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