SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b49003b946155340f44b667857c4696004991ceff02e7a4bb4afdde433186d8' 
  AND token = 'zvKipjTQKASd6wnWcrE4+8ZcTUr2xmLAdEDhoBNMRFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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