SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8a0ef8fd6fa04da6bb272739cc3b312184e052df7682d6cd404a170d1b0f8a5' 
  AND token = '97BGPUVKOd+AcQZiG8DptmxIudtCrkPGhk6NL/vg9Q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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