SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '616ce3d6970455b928988f2887a8c21f7d48dec3112517007394993c89f9f28a' 
  AND token = 'nJC4ES2W9hjbJZtK8PLsYFyRXiMzYqHUFzLR+YxeW0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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