SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c62b152fe075c8ca45f1013ab4536324346fcf88f931525a4b2ae79a84edcf2' 
  AND token = '/ignlpHxB8YNYRBX9BbwTpX+Xkld+RPYbB7IwVvs/Ww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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