SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57f99353eb19ce88398f4ac3d789cc3e1a282d0b03df5f6edcb1b44a8defb2ee' 
  AND token = 'S2PeOVDP+iAiW4+pJBMnaoijiBvfjzi2h8vgt0ZNhek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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