SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7680131f904010a37983c514de86f798f7b92df73729f09c0e5a13d7454127da' 
  AND token = 'f+PpozVuOr7KAZkx5tSoXuAAnFiywbKsEXRb72OFZXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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