SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '237c411227e774a7a620d168cdbd4107fb258fa0a0f44ee7f4bb4794b26820d4' 
  AND token = '3UPuQaOduAEtGiXkeEa9qUtDj40HutVDb72gD9M3Ccc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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