SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9baa51c51bab3c72dc676e96e2b9c0a9094ca6fd152bf9d7f2296386d2bae5d' 
  AND token = 'biP5HZJVy++OOqqqhGjuyR/X4JVdFCcZdnr/HVfgXrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}