SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c612fc2edc099d48b2910d8dfc5f8ad8e781980a34e82076a6d25cd18d954685' 
  AND token = 'OAOqGB3czLgoGhjhkUkhY+47Fwu0vJJfPcvY44vxZEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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