SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adec51f426b582c8e4a431e9cd11cc764da01f8374abbbd59acf6031352c6971' 
  AND token = 'VmzoXxaMJ80AREK+I4NmU0wOkJj8pg4ruxGQJcayQ8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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