SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f99f949db57705551b800b310dc33d6aeedc1e896745d1bfa11400e2fcc6454' 
  AND token = 'JuNk5jn9A2wxF6PkxkO6KClZAObxxJ5vc8TiCQ4I/Bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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