SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2fb504acaa7c3fbd9d2a3259b07c643abfc1f9958e2d406d099195156ec7d5d' 
  AND token = 'SCcl6yGwjRQ4SJn6L2fKiM2adu6VLxlUxTGdowowcpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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