SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c36bcf375ec44550311f5f9bcd5d0b8212744c163678892bdd5a10ea349a1b2' 
  AND token = 'gPgGxSZ6d986RjB8HXizny+1FnW+dpZ4/Dyc2WqFiTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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