SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '258df2f9548786ef010eb03d63ea7efe6641fe119f2026eec1fde47f42dfb680' 
  AND token = 'KQYM8Z5XGasKHbwzCe6aWEEo3NAQVPcd4JJynJVOOKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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