SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c16aa3a31b652915287a1db5a3d8ffbfcd18f8b10c48822b25bf6db01accc7e9' 
  AND token = '5MW9a0iUz9t+tcst1FEvZPpnkpB+frnqKLbmLgNdmuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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