SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a192c95f350d2d8696e01dfffe43c83540c5c4615bf1e31c2ebfce70bf19892f' 
  AND token = 'drd8lp5IMmIdkYqk+yJMWnuBU6bXs3zb1c7+sVqAGRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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