SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7df8713d5edf53612b2d1e6b22c3aee28e8bd44c4277e77ebf637263415bfc36' 
  AND token = '7dDcsJITp76D847wqkpXo1e1XppzWIgIlup+pxdDZiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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