SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b199a2dc797381b63d0b31272ffd2d931fbf062c046cc89ff548a8ee29e545fc' 
  AND token = 'WGZsMQWWyBJwJoDn1nGsy7bKxuYGZR/iGLypQgkhby0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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