SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0b51a8b2005245a262e1855fb16e8922d17924a0d03f19fc17ec5838273a26e' 
  AND token = 'gIrag/scdZxozKiE3k0NffplavWrcSRKBxl42FfRJNM=' 
  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"
    }
  }
}