SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd7a51d3057c79115d3c5f56c00933590e07757d848aa6bf876b07bf25b9d06a' 
  AND token = 'hV2AERwEzXEUS+reTvEFB/m0ln4GaKjIi/6QYsPDIi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}