SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '710e31a986b09009c747b8808f87d49e6cf38c664fcbcddf8035a68c3b071e69' 
  AND token = 'ej1+nNJ5kSAJciyxFCUjOT5gNm8ygNeXiYnBhAttEdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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