SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5164222d35057e7df184edb0dd3ddc6dd6f8ba6a4f16e714f4e483f36de150e6' 
  AND token = 'xhu9Kv2ZN5zOiDYXGqkJjYJ+ncG6VA6Bh0IUHkkMyVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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