SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4356559c777801e2f66244cbeace29cf2451626a5fa1c9b4201abd1c4fa0ab7e' 
  AND token = 'N6tlGwLWYCiPnmN7kmy/QEiDzpPEeCi16Gc7C9qaFm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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