SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a155fcf84f2036c075df04ab04784eede3741c2c89cb68635347f3275c43cf81' 
  AND token = 'RJfzY8gx9NtQrNb9NisnO4ET2kRty6GDbw09YZKbnvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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