SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a13971646df41e2ff442abc6d618b1b1dae33913b3bcf2141937464ad8fac36f' 
  AND token = 'tbHLP/qqcvxY9LbPTRAatxpSU9LLrgiEN6YLF4236qQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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