SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be97b64c2e573dd5aa35d24b198370ddffa60962403f5850804a195b6e901be4' 
  AND token = 'sT/xXX6rHlljihWzb8MAZKwJIZjxFZPSHoUfymVJhzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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