SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5e63b8f85ca8eae52eaa536ec3a1bdd9d5c1a9be67e9717492dd140561cbde3' 
  AND token = 'qiYDw4bkkNE7dXe3xTK4RlGTqfc+KjWp5nqNDKjdBLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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