SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd76dfc6bc3d9b90427c8f5b0eaafe31baaf169ef056a517f6c6012970f236bd' 
  AND token = '4IBqjcvUFbryUFp92YuZW4CFoasVOGyc3FheY/IczFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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