SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0950b543d1f105b875e200e1f858446786eaa831299517634eab9e5be7bd350' 
  AND token = 'rbmMX276U0IT8up1bdWyg+LplM+kYwdJSVBQRsMfnsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}