SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '076855df32bc4e2dcf607812d2273af4eca739885969df7e526fbf70c015c122' 
  AND token = 'Fo8kFIzH89QNXBXAnu8Ub1jJs16bxaaqKOPJhrUbnbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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