SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34b2b054f3bcd528af52284cd068039195f121c70858a5bbb023fd7dc0e3140e' 
  AND token = 'EPxtWm/UuDjQUBj5ZovAliE6ziPkPCmgKDhmg6F7LrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}