SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18ef7f417730525c2b067f62c3b3168aff60431574da9d615099d3d7d3557428' 
  AND token = 'C/ZQaskeLT7VOw1oVtTNG8bHp/EYlRCmwI44eojjuig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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