SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b84fca61e2124ad3b0964fd00f7f23bbec4f9598ad07a874669ffad0fa915e3' 
  AND token = '4XUA/CdlREJ7RDiYJAc6wgPHWvSH1R9WqQrvYUnT6HY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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