SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b249378495aa5be5b8e8d912302d6e0c1a1548f815df552be744329b49ece85d' 
  AND token = '+mVj4Z3j3dFb7a3KosEV6+xBERsu+oWSFjkoc7ohejs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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