SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af455e244636a7f957d5c8004a76e60bf08bbcd2ebcce755148acb9ece3bfa13' 
  AND token = 'qFGKbk43UXxoWkHTP9Sa5lNMtiz5Q9ucwEPT28XKCPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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