SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '690a68abceb0745d4722d91dd48912e3aa57b899b51658625a21ba2dc9557476' 
  AND token = 'W12Ky6zGVtRLxaEglR3T4Bheazvu3iVEtJ/bKprkOaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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