SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4274a8db5e9bb01b943b42fa157a2245dddda8219aab2ce1d0709ecb8b134a3d' 
  AND token = 'x932x/ewwUYtKSBZfIWeNrfGkmjQUDCTODSMTDcMgSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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